Abstract: HealthRhythms, Inc. Substantial evidence supports the idea that disruptions in the regularity of behavioral routines (or ?social rhythms?) can lead to the onset of psychiatric symptoms and full blown episodes via their impact on endogenous circadian rhythms and, conversely that stable social routines protect against new mood episodes. Based on our conviction that monitoring, evaluating, and increasing the regularity of behavioral rhythms has broad applicability for improving mental health, we established HealthRhythms, Inc. (www.healthrhythms.com) with the goal of using mobile technology to add the layer of mental health care to all of healthcare. Our product model capitalizes on the ubiquity and intimacy of smartphones and their capacity to sense parameters of behavior that represent key indicators of mental health on a 24/7 basis captured in the user?s natural environment, opposed to the sporadic, in-clinic measurement that has characterized mental healthcare to date. The product we envision will ultimately have three pillars: Rhythm Sensing, Rhythm Trending, and Rhythm Stabilization. The first two of these pillars have been developed and thousands of licenses for our product have already been sold. Building on our accomplishments to date, this SBIR Phase II Direct proposal extends our work in three ways: 1) further validating our existing technology, 2) developing the next stage of our technology and 3) expanding and improving our prediction models and demonstrating the cost-effectiveness of our technology. The Specific Aims are: Aim 1: Enhance our Rhythm Trending capabilities through intensive examination and analysis of data from the 3,000+ patients with whom our product has already been deployed. Aim 2: Develop the envisioned Rhythm Stabilization pillar of our technology. Aim 3: Expand the nature of the data included in our prediction models and demonstrate their utility.